East Sunbury suffered a second successive one-point loss in Essendon District Football League division 2.
Looking to seal a finals spot for the first time, the Thunder will have to wait at least another week after losing to Roxburgh Park on Saturday.
The Thunder jumped out of the blocks against the Magpies with four goals to one in the first quarter.
But the Magpies, coming back from a week off, hit back in the second quarter to lead by 10 points at the main break.
The lead changed hands again in the third quarter, with the Thunder having their best quarter, kicking five goals and taking a nine-point lead into the final change.
Just three goals were kicked in the final quarter.
The Magpies failed to make the most of their opportunities but grabbed the lead and eventually the win, 10.9 (69)-10.8 (68).
The loss reduces the gap between East Sunbury and Coburg Districts to just four points. Coburg Districts also has a better percentage.
The Thunder this week face top side Moonee Valley. They then have a bye, before facing Coburg Districts in the final round.
In other results, Moonee Valley won the battle of the top two sides against Northern Saints, while Burnside Heights defeated Hadfield.
Tara Murray
